The Maine Center for Disease Control and Prevention on Thursday confirmed that a student has been diagnosed with mumps, the state’s first case since 2013.

School spokesman Bob Stein says the student lives off campus and that the school contacted 155 students who might have come into contact with the student. Four have not been vaccinated. Blood tests showed that three of the four do not have mumps.

Officials say the student is no longer considered contagious and has been cleared to return to classes.

A CDC spokesman says the state is investigating a possible link between the case in Maine and a mumps outbreak at St. Anselm College in New Hampshire.